1. Field of the Invention
The present invention relates to a method of producing a base plate for an ink print head used in ink jet printers. The base plate, which is of a photosensitive glass material, is provided, by surface etching, with ink pressure chambers (ink printing chambers), ink channels and at least two rows of nozzle outlet openings.
2. Technology Review
An ink print head for use in ink jet printers generally includes a simple discharge (ejection) opening for ink, an ink channel and a part which generates the energy for ejecting the ink and which is situated in one part of the ink channel. According to a known method of making such an ink print head, in a plate, made, for example, of glass or metal, a fine trough is formed by cutting, machining or etching and then the plate is connected with another suitable plate to thus form an ink channel.
U.S. Pat. No. 4,096,626 discloses a method of producing a charge plate intended for charging ink droplets produced in ink jet printers. This plate is composed of several plate-shaped layers. Since these plates are composed of a photosensitive material which melts when heated, it is easy to etch in the passage holes that will serve as ink channels. However, after producing the individual plates, they must be interconnected by a suitable method. For this purpose, it is necessary to align the passage holes in the individual plates with one another. This requires significant precision and is thus expensive. This method is excessively complicated and expensive particularly for making ink print heads having a plurality of ink discharge openings arranged in several rows.
Because of the density patterns of 1/180" or 1/240" required for high print quality, it is often necessary to use more than one row of nozzles for each ink color in the massproduced ink print heads. If, for example, two rows of nozzles are disposed in two independent heads, they must be adjusted very precisely both vertically and horizontally with respect to one another. If the nozzles are part of individual, mirror-image symmetrical heads, the heads must be glued or welded together by mean of pin guides and fitting holes. In such a method the degree of precision of the pin guidance determines the attainable vertical accuracy and the sum of the thickness tolerances of the head plates determines the horizontal pattern quality.